I NEed Help

ok i’m making a circuit that uses a 6v max solar panel for power

i want to charge my circuit off this running to a 5v (nimh) battery

but when it hits 5v i want to stop charging the positive pole coming off of my regulator

so look

solar panel->(regulator=batteries->+circuit)

so the solar panel connects to the regulator which feed my battery and runs to my circuit board is there a way to do this electronicly or am i going to have to put an a chip on the board and program it to do this?